Cooling system for heat generating components in a fairing

ABSTRACT

A rotor system includes a rotor hub, a plurality of rotor blades supported by the rotor hub, and a fairing mounted to the rotor hub. The fairing includes an external surface exposed to an external airflow and an internal surface defining an interior portion. One or more heat generating components are arranged in the interior portion. A cooling system is arranged in the interior portion. The cooling system includes a first heat exchanger thermally connected to each of the one or more heat generating components, a second heat exchanger mounted to the fairing, and at least one fluid conduit extending therebetween so as to remove heat generated by each of the one or more heat generating components.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. Non-Provisional applicationSer. No. 15/646,527, filed Jul. 11, 2017, which is incorporated hereinby reference in its entirety.

BACKGROUND

Exemplary embodiments pertain to the art of rotary wing aircraft and,more particularly, to a cooling system for rotor blade actuators for arotary wing aircraft.

Rotary wing aircraft include rotor blades that are selectively rotatedabout a rotor blade axis to adjust flight characteristics. Typically,each rotor blade of a rotor system is connected to a rotor bladeactuator which, in turn, may be coupled to a vehicle management systemand/or control inceptors. In some cases, rotor blade actuators may beexposed to an airstream passing over or around a rotor hub. In othercases, the rotor blade actuators may be surrounded in a fairing. Thefairing reduces drag on the rotor blades. The fairing also reducesairflow across the actuators which, in turn, can have a detrimentaleffect on cooling.

BRIEF DESCRIPTION

Disclosed is a rotor system including a rotor hub, a plurality of rotorblades supported by the rotor hub, and a fairing mounted to the rotorhub. The fairing includes an external surface exposed to an externalairflow and an internal surface defining an interior portion. One ormore heat generating components are arranged in the interior portion. Acooling system is arranged in the interior portion. The cooling systemincludes a first heat exchanger thermally connected to each of the oneor more heat generating components, a second heat exchanger mounted tothe fairing, and at least one fluid conduit extending therebetween so asto remove heat generated by each of the one or more heat generatingcomponents.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include wherein the secondheat exchanger includes a surface portion exposed at the externalsurface of the fairing.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include wherein the fairingincludes an upper portion and a lower portion, the second heat exchangerbeing arranged at the lower portion.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include wherein the fairingincludes an upper portion and a lower portion, the second heat exchangerbeing arranged at the upper portion.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include wherein the atleast one fluid conduit comprises a heat pipe.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include a fluid arranged inthe cooling system.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include wherein the atleast one fluid conduit includes a first fluid conduit delivering fluidfrom the second heat exchanger to the first heat exchanger and a secondfluid conduit delivering fluid from the first heat exchanger to thesecond heat exchanger.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include a pump fluidicallyconnected to the second fluid conduit.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include wherein the secondheat exchanger extends about at least a portion of the fairing, whereinthe first heat exchanger of each of the one or more heat generatingcomponents is fluidically connected to the second heat exchanger.

Also disclosed is a method of cooling one or more heat generatingcomponents arranged in a rotor hub fairing includes promoting a heatexchange between a cooling fluid in a first heat exchanger and each ofthe one or more heat generating components, passing the cooling fluid toa second heat exchanger arranged on a fairing surrounding the hub end ofeach of the plurality of rotor blades, and promoting a heat exchangebetween the cooling fluid in the second heat exchanger and ambientfluids in contact with an external surface of the second heat exchanger.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include wherein passing thecooling fluid to the second heat exchanger includes passing the coolingfluid through a heat pipe.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include wherein passing thecooling fluid to the second heat exchanger includes passing the coolingfluid to an annular heat exchanger having a surface externally exposedon the fairing.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include passing the coolingfluid from the second heat exchanger back to the first heat exchanger.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include wherein passing thecooling fluid back to the first heat exchanger includes pumping thecooling fluid back to the first heat exchanger.

In addition to one or more of the features described above or below, oras an alternative, further embodiments could include wherein passing thecooling fluid back to the first heat exchanger includes guiding thecooling fluid with one of a centrifugal force and a gravitational force.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 depicts a vertical takeoff and landing (VTOL) aircraft includinga rotor blade actuator cooling system, in accordance with an exemplaryembodiment;

FIG. 2 depicts the rotor blade actuator cooling system, in accordancewith an exemplary embodiment;

FIG. 3 depicts a side view of a fairing surrounding the rotor bladeactuator cooling system, in accordance with an aspect of an exemplaryembodiment;

FIG. 4 depicts a bottom view of the fairing of FIG. 3, in accordancewith an aspect of an exemplary embodiment;

FIG. 5 depicts the rotor blade actuator cooling system, in accordancewith another aspect of an exemplary embodiment;

FIG. 6 depicts the rotor blade actuator cooling system, in accordancewith yet another aspect of an exemplary embodiment; and

FIG. 7 depicts the rotor blade actuator cooling system, in accordancewith still yet another aspect of an exemplary embodiment.

DETAILED DESCRIPTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

FIG. 1 depicts a vertical takeoff and landing (VTOL) aircraft 10including a dual, contra-rotating main rotor system 12, which rotatesabout a main rotor axis R. Aircraft 10 includes an airframe 14 whichsupports dual, contra-rotating main rotor system 12. Dual,contra-rotating main rotor system 12 includes a first rotor system 16and a second rotor system 18. First rotor system 16 includes a firstplurality of rotor blades 20 and second rotor system 18 includes asecond plurality of rotor blades 22. First plurality of rotor blades 20are mounted to a first rotor hub 24 and second plurality of rotor blades22 are mounted to a second rotor hub 26. Dual, contra-rotating mainrotor system 12 is driven by a gear box 28 coupled to one or more primemovers, indicated generally at 30. It should be understood that VTOLaircraft 10 may also be configured with a single rotor system or anyother rotor system having an enclosed hub and electronic actuators.

Aircraft 10 includes an extending tail 40 that supports a translationalthrust system 42 including a pusher propeller 44 that rotates about apusher propeller axis P. Translational thrust system 42 may beoperatively coupled to gear box 28 through a drive shaft 46.Translational thrust system 42 provides thrust along an aircraftlongitudinal axis L. It is to be understood that translational thrustsystem 42 may take on a variety of forms including those providing yawcontrol. Additionally, it should be noted that translational thrustsystem 42 may be any propeller system including a tractor propeller, anacelle mounted propeller, a wing mounted propeller, and the like.

Reference will now follow to FIG. 2, and with continued reference toFIG. 1 in describing first rotor system 16 with an understanding thatsecond rotor system 18 may include similar components. Each of theplurality of rotor blades 20, 22 includes a hub end, two of which areindicated at 52 and 53 connected to first rotor hub 24. A plurality ofrotor blade actuators 55 are mechanically connected to each of theplurality of rotor blades 20, 22. For example, a first rotor bladeactuator 56 is mechanically connected with hub end 52 and a second rotorblade actuator 58 is mechanically coupled with hub end 53. It is to beunderstood that each of the plurality of rotor blades 20, 22 includes acorresponding rotor hub actuator so as to define an individual bladecontrol (IBC) system for aircraft 10. A fairing 60 surrounds first rotorhub 24.

Fairing 60 includes an external surface 64 and an internal surface 66that defines an interior portion 68. Fairing 60 also includes an upperportion 70 and a lower portion 72. Each rotor blade actuator 56, 58, aswell as additional rotor blade actuators (not shown) are housed withininterior portion 68. As external surface 64 of fairing 60 issubstantially continuous, a cooling system 80 is provided to reduceoperating temperatures of each of the plurality of rotor blade actuators55.

Reference will continue to FIG. 2 in describing cooling system 80associated with second rotor blade actuator 58. It is to be understoodthat cooling system 80 includes cooling components associated with eachof the plurality of rotor blade actuators 55. Cooling system 80 includesa first heat exchanger 84 thermally connected to second rotor bladeactuator 58, a second heat exchanger 86 thermally connected to fairing60, and a fluid conduit 88 extending therebetween. Second heat exchanger86 may be arranged close to an axis of rotation of rotor system 16. Inan embodiment, second heat exchanger 86 is arranged inboard of eachrotor blade actuator 56, 58.

In accordance with an exemplary aspect, fluid conduit 88 fluidicallyconnects first heat exchanger 84 with second heat exchanger 86. In anembodiment, fluid conduit 88 may take the form of a heat pipe 90. Theterm “heat pipe” should be understood to describe a heat transfer devicethat combines thermal conductivity principles and phase transitionprinciples to manage a transfer of heat between two bodies. Fluidconduit 88 may take on other forms as well.

Second heat exchanger 86 includes an external surface portion 94 that isexposed at external surface 64 of fairing 60. In an embodiment, eachsecond heat exchanger 86 is a discrete element associated with acorresponding one of the plurality of rotor blade actuators 55. Inanother embodiment, second heat exchanger 86 may be associated with eachof the plurality of rotor blade actuators 55. As shown in FIGS. 3 and 4,second heat exchanger 86 may be an annular member (not separatelylabeled) with external surface portion 94 being substantially continuousand extending about lower portion 72 of fairing 60. It is to beunderstood that the particular arrangement, configuration and positionof second heat exchanger 86 may vary as discussed herein.

As shown in FIG. 5, wherein like reference numbers representcorresponding parts in the respective views, second heat exchanger 86may be arranged such that external surface portion 94 is exposed atupper portion 70 of fairing 60. That is, second heat exchanger 86 maytake the form of discrete heat exchangers arranged at upper portion 70of fairing 60. In FIG. 6, wherein like reference numbers representcorresponding parts in the respective views, second heat exchanger 86 isdepicted as an annular member that is fluidically connected to each ofthe plurality of rotor blade actuators 55 through a corresponding fluidconduit 88. It should also be understood that cooling system 80 mayinclude a second heat exchanger 86 at lower portion 72 of fairing 60 andanother second heat exchanger 86 at upper portion 70 of fairing 60.

In operation, a cooling fluid 100, which may be in the form of a liquidis forced from second heat exchanger 86 to first heat exchanger 84. Inan embodiment, cooling fluid 100 may be forced through centrifugal forcedeveloped through rotation of the first plurality of rotor blades 20. Inanother embodiment, the cooling fluid 100 may be forced from second heatexchanger 86 to first heat exchanger 84 by gravity. If by gravity,cooling system 80 may be operable without rotation of the plurality ofrotor blades 20 such as during ground maintenance or prior to spin up.

Cooling fluid 100 exchanges heat with second rotor blade actuator 58 andmay transform into a vapor 102. Vapor 102 returns through, for example,centrifugal force developed by rotation of rotor system 16. It should beunderstood that in addition to, or as an alternative to centrifugalforce, vapor 102 may be retried through a capillary action along heatpipe 90 to second heat exchanger 86. It should be further understoodthat heat pipe 90 may also take the form of a thermosiphon. Further, itis to be understood that vapor 102 may return under a gravitationalforce In second heat exchanger 86, vapor 102 transforms back to a liquidthrough a heat exchange with ambient and is passed back to first heatexchanger 84. In this manner, cooling system 80 may reduce localizedtemperatures at each of the plurality of rotor blades 20 without theneed to create openings in fairing 60 which could create undesirabledrag. Further, the above described system provides a closed loop coolingsystem that does not require electrical connections or external power toguide cooling fluid between two heat exchangers.

Reference will now follow to FIG. 7, wherein like reference numbersrepresent corresponding parts in the respective views, in describing afluid conduit 140 in accordance with another aspect of an exemplaryembodiment. Fluid conduit 140 includes a first conduit member 142 thatextends between and fluidically connected first heat exchanger 84 andsecond heat exchanger 86 and a second conduit member 144 that extendsbetween and fluidically connects first heat exchanger 84 and second heatexchanger 86. Second conduit member 144 delivers cooling fluid 100,which may be in the form of a liquid or a vapor from first heatexchanger 84 to second heat exchanger 86. First conduit member 142delivers cooling fluid 100, which may be in the form of a liquid fromfirst heat exchanger 84 to second heat exchanger 86. In order to promotemovement of cooling fluid 100, cooling system 80 includes a pump 146fluidically connected with first conduit member 142. In thisconfiguration, pump 146 operates to transfer cooling fluid 100 fromsecond heat exchanger 86 back to first heat exchanger 84.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentdisclosure. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,element components, and/or groups thereof.

While the present disclosure has been described with reference to anexemplary embodiment or embodiments, it will be understood by thoseskilled in the art that various changes may be made and equivalents maybe substituted for elements thereof without departing from the scope ofthe present disclosure. In addition, many modifications may be made toadapt a particular situation or material to the teachings of the presentdisclosure without departing from the essential scope thereof.Therefore, it is intended that the present disclosure not be limited tothe particular embodiment disclosed as the best mode contemplated forcarrying out this present disclosure, but that the present disclosurewill include all embodiments falling within the scope of the claims.

What is claimed is:
 1. A rotor system comprising: a rotor hub; aplurality of rotor blades supported by the rotor hub; a fairing mountedto the rotor hub, the fairing including an external surface exposed toan external airflow and an internal surface defining an interiorportion; and a cooling system arranged in the interior portion, thecooling system including a first heat exchanger and, a second heatexchanger which is mounted to the fairing, and at least one fluidconduit extending therebetween so as to remove heat generated within theinterior portion of the fairing.
 2. The rotor system according to claim1, wherein the second heat exchanger includes a surface portion exposedat the external surface of the fairing.
 3. The rotor system according toclaim 2, wherein the fairing includes an upper portion and a lowerportion, the second heat exchanger being arranged at the lower portion.4. The rotor system according to claim 2, wherein the fairing includesan upper portion and a lower portion, the second heat exchanger beingarranged at the upper portion.
 5. The rotor system according to claim 1,wherein the at least one fluid conduit comprises a heat pipe.
 6. Therotor system according to claim 1, further comprising: a fluid arrangedin the cooling system.
 7. The rotor system according to claim 1, whereinthe at least one fluid conduit includes a first fluid conduit deliveringfluid from the second heat exchanger to the first heat exchanger and asecond fluid conduit delivering fluid from the first heat exchanger tothe second heat exchanger.
 8. The rotor system according to claim 7,further comprising: a pump fluidically connected to the second fluidconduit.
 9. The rotor system according to claim 1, wherein the secondheat exchanger extends about at least a portion of the fairing.
 10. Amethod of cooling an interior portion within a rotor hub fairing, themethod comprising: promoting heat exchange between a cooling fluid in afirst heat exchanger and the interior portion of the rotor hub fairing;passing the cooling fluid to flow in a fluid conduit extending betweenthe first heat exchanger and a second heat exchanger arranged on thefairing in which a plurality of rotor blades are housed; and promotingheat exchange between the cooling fluid in the second heat exchanger andambient fluids in contact with an external surface of the second heatexchanger.
 11. The method of claim 10, wherein the first heat exchangerand the second heat exchanger are connected by the fluid conduit. 12.The method of claim 10, further comprising passing the cooling fluid toan annular heat exchanger having a surface externally exposed on thefairing.
 13. The method of claim 10, further comprising: passing thecooling fluid from the second heat exchanger back to the first heatexchanger.
 14. The method of claim 13, wherein passing the cooling fluidback to the first heat exchanger includes pumping the cooling fluid backto the first heat exchanger.
 15. The method of claim 13, wherein passingthe cooling fluid back to the first heat exchanger includes guiding thecooling fluid with one of a centrifugal force and a gravitational force.16. The rotor system according to claim 1, further comprising one ormore heat generating actuators arranged in the interior portion, whereinthe first heat exchanger is thermally connected to each of the one ormore heat generating actuators.
 17. The method of claim 10, wherein theinterior of the rotor hub fairing includes at least one heat generatingcomponent comprising an actuator.